In recent years, display devices including function panels such as touch panels, viewing angle control panels, and parallax barrier panels, along with liquid crystal panels that display images and the like are known (refer to Patent Document 1, for example). In these types of display devices, the above-mentioned function panel as an auxiliary panel is bonded to a surface of the liquid crystal panel as a main panel through an adhesive.
As the adhesive, in general, a photocurable (photosensitive) adhesive is used. Such a photocurable adhesive is liquid before being cured by being irradiated with light such as ultraviolet, and has fluidity. When bonding together the main panel and the auxiliary panel, this fluid adhesive is first applied to a surface of the main panel. The auxiliary panel is stacked onto the surface of the main panel so as to sandwich the adhesive applied in this manner. Then, respective positions of the main panel and the auxiliary panel are set and the adhesive is irradiated with light such as ultraviolet light, thus bonding together the main panel and the auxiliary panel.
If the adhesive layer between the main panel and the auxiliary panel has an uneven thickness, then variation occurs in the distance (gap) between the main panel and the auxiliary panel. This sometimes causes display unevenness such as color unevenness in the image in the main panel perceived by a user through the auxiliary panel. Thus, in order to provide the adhesive layer with an even thickness, while the adhesive is still fluid, the adhesive is thinly spread between the main panel and the auxiliary panel so as to be flat.
In general, a polarizing plate is provided on the topmost surface of the main panel (liquid crystal panel). Thus, specifically, the adhesive is thinly spread as described above between the polarizing plate and the auxiliary panel. Generally, the polarizing plate is somewhat smaller than the main body of the main panel (liquid crystal panel), and the periphery of the polarizing plate is to the inside of the periphery of the main panel.
Some of the adhesive seeps towards the outside from between the polarizing plate and the auxiliary panel. Among the adhesive that seeps out, some of the adhesive reaches the surface of the main body of the main panel further out than the periphery of the polarizing plate, causing it to cover the periphery of the polarizing plate.
The polarizing plate is easily affected by humidity, and swells if it absorbs water (moisture) from the outside air, and thus, the polarizing plate sometimes undergoes a change in thickness. Swelling in the polarizing plate is sometimes a cause for the display unevenness described above. Thus, the periphery of the polarizing plate is covered by the adhesive.